Here is the full list of all 16 Dungeons of Legend: Cast Within achievements.
Try all potion types.
Equip a full class set.
Drink a hundred potions.
Kill 30 snakes.
Beat the game on hardcore.
Discover 10 secrets.
Discover 25 secrets.
Find a friend in need.
Kill 20 undead creatures with the Harm Undead spell.
Unlock all spells.
Discover a pact made in darkness.
Gimme the next number.
Defeat the Dark Knight.
Clean up the Haunted Halls.
Was he knight or was he knave? Precarious waters did you brave.
Beat the game on Old School Mode.